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Visitor
Visitor
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Registered: ‎06-05-2019

Timing analysis for different temperature grade parts

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Hi,

I have a design targeted to a Kintex 7 FPGA and I had to do some timing analysis on this.

I am using an industrial grade part in the ISE 14.6 tool.

The PAR report mentions that the analysis is done over the temperature range of 0 - 85 degrees.

Is it possible to change this setting?

I did search other answers and found out that a single speed file is used and 85 degrees corresponds to 100 degrees in industrial grade parts.

Can we also assume that 0 degrees corresponds to -40 degrees for industrial parts too?

I just want to ensure that hold time violations will not occur below 0 degree.

My design does meet all timing requirements in the range of 0 - 85 but the slack is very close to 0 (1 ps at minimum).

 

Thanks,

Jim

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Moderator
Moderator
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Registered: ‎11-04-2010

Hi, @jimcolaco ,

For 7-series device, TEMPERATURE prorating is not supported. 

For the device with same package and speed grade, the speed model for commercial device (0~85) is same as the one of industrial device (-40~100).  

 

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Scholar
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Registered: ‎08-07-2014

@jimcolaco,

I have a design targeted to a Kintex 7 FPGA and I had to do some timing analysis on this.

I am using an industrial grade part in the ISE 14.6 tool.

Allow me to point out a blunder. For 7 series FPGAs, ISE tool is NOT recommended.  Use Vivado.

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Visitor
Visitor
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Registered: ‎06-05-2019
Thanks for the reply @dpaul24
This is a legacy design. I just did a few enhancements without changing any other project specific settings.
Just wanted some help in understanding the timing analysis targeting different temperature grades.
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Teacher
Teacher
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Registered: ‎07-09-2009

Regarding the slack,

 

If the report say sit works at 0 degrees, then Xilinx have taken care of al the Process, voltage , temprature, self heating questoins for you , and built in an 'appropreate' safety margin.

 

QED. if it says its Ok at 0 degrees, than its Ok,

   no need to add your own margin,

 

 

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Teacher
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Registered: ‎07-09-2009

This might help 'for some devices'

 

https://www.xilinx.com/support/documentation/sw_manuals/xilinx11/pce_p_operatingconditions.htm

 

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Visitor
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Registered: ‎06-05-2019

Thanks for the reply @drjohnsmith .

I know for a fact that older devices had an option for prorating using the TEMPERATURE constraint.

I believe this constraint unfortunately is not supported for the 7 series devices.

I am hoping that Trace will guarantee operation throughout the temperature range for industrial parts but I wanted a confirmation of the same from anyone at Xilinx or anyone that has interacted with Xilinx about this.

I have a PAR report for another project targeting Virtex-4 which contains a clear mention of the temperature range being -40 degrees to 100 degrees.

The Kintex 7 PAR report however mentions only 0 degrees to 85 degrees.

 

Left : Virtex-4 PAR report Right : Kintex7 PAR reportLeft : Virtex-4 PAR report Right : Kintex7 PAR report

 

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Moderator
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Registered: ‎11-04-2010

Hi, @jimcolaco ,

For 7-series device, TEMPERATURE prorating is not supported. 

For the device with same package and speed grade, the speed model for commercial device (0~85) is same as the one of industrial device (-40~100).  

 

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Visitor
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Registered: ‎06-05-2019
Hi @hongh,
Thanks for clearing the confusion.
As you have suggested, I will consider the timing report to hold true for all temperature grades.
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Teacher
Teacher
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Registered: ‎07-09-2009

Id imagine the virtex was a industrial or such part, whilst the kintex is the comercial part.

  hence the temprature difference.

 

Sorry about the config constraint not working, I was wondering if the 7 was supported,

 

 

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